Wrong usage of CANopen protocol

[neojaw]

The current code will not work with strictly CANopen compliant devices, e.g. Elmo Gold controllers.

• Heartbeats are sent as 5 byte long CAN frames on CAN id 0x700. The CAN id should be 0x700 + node_id where node_id is the node ID of the SPS (which should exist as a parameter). The size should be one byte, describing the node state (usually "operational", i.e. 5).
• Related, in configure_watchdog(), the devices are told to listen for heartbeats from node 0 when instead they should listen to the node ID of the SPS.
• In configure_PDO_mapping(), the PDO message must be disabled at the beginning and enabled at the end:

  canopen_SDO_download(motor, 0x1800, 1, 0x80000000+motor.can_Tx_PDO1);
  [...]
  canopen_SDO_download(motor, 0x1800, 1, 0x40000000+motor.can_Tx_PDO1);

[padhupradheep]

The CAN id should be 0x700 + node_id where node_id

That means, we are right now sending the heartbeat only to one motor controller right?

the PDO message must be disabled at the beginning and enabled at the end:

to avoid interruptions?

[neojaw]

The CAN id should be 0x700 + node_id where node_id

That means, we are right now sending the heartbeat only to one motor controller right?

No, right now we are not sending a valid heartbeat at all. A heartbeat message is always a broadcast message that is received and processed by all the nodes ("Hey everybody, I am node X and I am fine!"). The CAN ID has to be 0x700 + node_id so that the receivers know which node it came from. Right now we use CAN ID 0x700 which would mean a node ID of 0 which does not exist in CANopen.

the PDO message must be disabled at the beginning and enabled at the end:

to avoid interruptions?

No, because the protocol says so. It only worked all this time because the motor controllers we were using didn't care much about protocol compliance.